The present invention relates to a food intake restriction apparatus and method. More specifically, the invention relates to a food intake restriction apparatus and method for surgical application in the abdomen of a patient for forming a restricted stoma opening in the stomach or esophagus. The term xe2x80x9cpatientxe2x80x9d includes an animal or a human being.
Food intake restriction apparatus in the form of a gastric banding device, in which a band encircles a portion of a patient""s stomach to restrict the food intake of the patient, have been used in surgery for morbid obesity to form a small gastric pouch above the band and a reduced stoma opening in the stomach. Although such a band is applied around the stomach to obtain an optimal stoma opening during surgery, some prior gastric banding devices are provided with an adjustment means enabling a minor post-operation adjustment of the size of the stoma opening. In all such prior art devices such as disclosed in U.S. Pat. No. 4,592,339, European Pat. No. 0611561 and International Patent Application WO 94/27504, the adjustment means typically comprises an inflatable cavity in the band and an injection port in fluid connection with the inflatable cavity for adding fluid to or withdrawing fluid from the latter. In practice, the band is made of silicone rubber which is a material approved for implantation and the fluid is a liquid such as an isotonic salt solution.
It has also been found that the volume of the gastric pouch above the band increases in size up to ten times after operation. Therefore the pouch volume during surgery needs to be very small, approximately 7 ml. To enable the patient to feed the stomach with sufficient nutrition immediately after an operation considering such a small gastric pouch, the stoma initially needs to be relatively large and later needs to be substantially reduced, as the pouch volume increases. To be able to achieve a significant range of adjustment of the band, the cavity in the band has to be relatively large and is defined by a thin flexible wall, normally made of silicone material. Furthermore, the size of the stoma opening has to be gradually reduced during the first year after surgery as the gastric pouch increases in size. As indicated above, the reduction of the stoma opening using the prior art devices is achieved by adding liquid to the cavity of the band via the injection port to expand the band radially inwardly.
A great disadvantage of repeatedly injecting liquid via the injection port is the increased risk of the patient getting an infection in the body area surrounding the injection port. If such an infection occurs the injection port has to be surgically removed from the patient. Moreover, such an infection might be spread along the tube interconnecting the injection port and the band to the stomach, causing even more serious complications. Thus, the stomach might be infected where it is in contact with the band, which might result in the band migrating through the wall of the stomach. Also, it is uncomfortable for the patient when the necessary, often many, post-operation adjustments of the stoma opening are carried out using an injection needle penetrating the skin of the patient into the injection port.
It may happen that the patient swallows pieces of food too large to pass through the restricted stoma opening. If that occurs the patient has to visit a doctor who can remove the food pieces, if the band design so permits, by withdrawing some liquid from the band to enlarge the stoma opening to allow the food pieces to pass the stoma. Then, the doctor has to add liquid to the band in order to regain the restricted stoma opening. Again, these measures require the use of an injection needle penetrating the skin of the patient, which is uncomfortable for the patient.
The object of the present invention is to provide a new convenient food intake restriction apparatus for forming a stoma opening in the stomach or esophagus of a patient which is easy to adjust and does not require the use of an injection needle for accomplishing post-operation adjustments of the stoma opening.
According to one aspect of the present invention a food intake restriction apparatus is provided which comprises: An energy transmission device for wireless transmission of energy of a first form from outside a patient""s body. An operable restriction device implanted in the patient and engaging the stomach or esophagus to form a restricted stoma opening in the stomach or esophagus, the device operable in response to a second energy form different than the first form to vary the restricted stoma opening. And, an energy transfer device implanted in the patient for transferring energy of the first form transmitted by the energy transmission device into energy of the second form, the energy transfer device comprising at least one element having a positive region and a negative region, and creating an energy field between the positive and negative regions when exposed to the first form energy transmitted by the energy transmission device, so that the energy field produces the energy of the second form.
As a result, the advantage is achieved that the food intake restriction apparatus of the invention provides simple and effective energy transmission which ensures an extended and reliable functionality of the apparatus, possibly for the rest of the patient""s natural life, and at least many years.
The restriction device preferably controls the size of the stoma opening in the stomach or esophagus, which gives the advantage that the patient can be permitted to temporarily increase the size of the stoma opening in case pieces of food get stuck in the stoma opening. It would be very difficult for the patient to remove a stuck food piece if the patient were unable to enlarge the size of the stoma opening.
Advantageously, the restriction device is directly operated with the energy of the second form, preferably in a non-magnetic and/or non-mechanical manner, as the energy transmission device transmits the energy of a first form. The restriction device may be directly operated with the energy of the second form without externally touching subcutaneously implanted components of the apparatus. The advantage of directly using energy as it is transmitted is that the apparatus can be of a very simple design and the few components involved makes the apparatus extremely reliable.
The restriction device may be non-inflatable, i.e. with no hydraulic or pneumatic fluid involved for the adjustments of the restriction device. This eliminates problems with fluid leaking from the restriction device.
In accordance with a preferred embodiment of the invention, the element comprises an electrical junction element, and the electrical junction element is capable of inducing an electric field between the positive and negative regions when exposed to the energy of a first form transmitted by the energy transmission device, whereby the energy of a second form comprises electric energy.
Consequently, the restriction device suitably is electrically operated, whereby the positive and negative regions of the electrical junction element supply electric energy for the operation of the restriction device. The apparatus suitably comprises implanted electric conductors connected to the positive and negative regions of the electrical junction element, whereby the electrical junction element is capable of supplying an electric current, such as a direct current, a pulsating direct current, a combination of a direct and pulsating direct current, an alternating current or a combination of a direct and alternating current, via the conductors. Furthermore, the electrical junction element may be capable of supplying a frequency, amplitude, or frequency and amplitude modulated analog, digital, or a combination of analog and digital signal, which is used in connection with control of the restriction device.
The element, preferably in the form of an electrical semiconductor junction element, suitably forms a flat and thin sheet and has a volume of less than 2000 cm3 to be suited for subcutaneous implantation, so that the electrical junction element is located just behind the skin of the patient. The electrical junction element should be designed to generate an output current exceeding 1 xcexcA when exposed to the energy of the first form transmitted by the energy transmission device. Of course, all the components of the energy transfer device including the electrical junction element in contact with the patient""s body should be of a biocompatible material. Alternatively, it would be possible to implant the energy transfer device in the thorax or cephal region of the patient, or in an orifice of the patient""s body and under the mucosa or intraluminar outside the mucosa of the orifice.
For in vitro appliances, a particular type of an electrical semiconductor junction element has been commonly used, namely a so called p-n (positive/negative) junction element, typically in the form of solar cells. A solar cell transfers solar energy in the form of visible light into electric energy in the form of direct current. For example, a p-n junction element may comprise two layers of semiconductor, one p-type (positive) and the other n-type (negative), sandwiched together to form a xe2x80x9cp-n junctionxe2x80x9d. This p-n junction induces an electric field across the element when absorbing quanta of light (photons).
To be more precise, the quanta of light transfer their energy to some of the semiconductor""s electrons, which are then able to move about through the material. For each such negatively charged electron, a corresponding positive chargexe2x80x94a xe2x80x9cholexe2x80x9dxe2x80x94is created. In an ordinary semiconductor, these electrons and holes recombine after a short time and their energy is wasted as heat. However, when the electrons and holes are swept across the p-n junction in opposite directions by the action of the electric field, the separation of charge induces a voltage across the p-n junction element. By connecting the p-n junction element to an external circuit, the electrons are able to flow thereby creating a current.
Surprisingly, it has been proven that although both the skin and subcutis absorb energy from an external light beam directed against the skin portion behind which a properly designed p-n junction element is located, the light energy transmitted through the skin can induce a current from the p-n junction element strong enough (minimum 1 xcexcA) to enable the operation of the electrically operated restriction device. Thus, such a p-n junction element is now for the first time used for in vivo applications.
However, the apparatus of the present invention is not limited to the use of visible light for the wireless transmission of energy. Thus, in accordance with a broad aspect of the invention, the energy transmission device transmits energy by at least one wireless signal, preferably containing radiant energy.
The wireless signal may comprises a wave signal, for example an electromagnetic wave signal, such as an infrared light signal, a visible light signal, an ultra violet light signal,a laser signal, a micro wave signal, a radio wave signal, an x-ray radiation signal, and a gamma radiation signal. Where applicable, one or more of the above signals may be combined. Alternatively, the wave signal may comprise a sound wave signal, such as an ultrasonic signal. Generally, the wireless signal may comprise a digital, analog or a digital and analog signal.
The energy of the first form transmitted by the energy transmission device may comprise an electric or magnetic field transmitted in pulses, for example digital pulses. Furthermore, the energy transfer device may transfer the energy of the first form, which may comprise polarized energy, into a direct current, pulsating direct current, a combination of a direct and pulsating direct current, an alternating current or a combination of a direct and alternating current. Alternatively, the energy of the first form may comprise kinetic energy.
The energy of the second form may comprise a frequency, amplitude or frequency and amplitude modulated analog, digital or combined analog and digital signal.
The apparatus may further comprise an implanted pulse generator for generating electrical pulses from the energy of the second form rendered by the energy field created by the element having positive and negative regions.
In accordance with another embodiment of the invention, the apparatus comprises an implanted operation device for operating the restriction device and a control device for controlling the operation device, wherein the element powers the operation device with the energy of the second form. The operation device preferably comprises a motor, for example an electric linear motor or an electric rotary motor which is controlled by the control device to rotate a desired number of revolutions. The electric motor may have electrically conductive parts made of plastics. Alternatively, the motor may comprise a hydraulic or pneumatic fluid motor, wherein the control device controls the fluid flow through the fluid motor. Motors currently available on the market are getting smaller and smaller. Furthermore, there is a great variety of control methods and miniaturized control equipment available. For example, a number of revolutions of a rotary motor may be analyzed by a Hall-element just a few mm in size.
In accordance with another embodiment of the invention, the restriction device comprises hydraulic means and the operation device comprises a pump for pumping a fluid in the hydraulic means, a motor for driving the pump, a valveless fluid conduit between the pump and the hydraulic means of the restriction device, and a reservoir for fluid, wherein the reservoir forms part of the conduit. All of the hydraulic components involved are preferably devoid of any non-return valve. This is of great advantage, because with valves involved there is always a risk of malfunction due to improperly working valves, especially when long time periods passes between valve operations. The reservoir may form a fluid chamber with a variable volume, and the pump may distribute fluid from the chamber to the hydraulic means of the restriction device by reduction of the volume of the chamber and withdraws fluid from the hydraulic means to the chamber by expansion of the volume of the chamber.
The control device may reverse the operation device by shifting polarity of the energy of the second form. Where the operation device comprises an electric motor the energy of the second form suitably comprises electric energy.
In accordance with yet another embodiment of the invention, the restriction device is operable to perform a reversible function, such as enlarging and restricting the food passageway, and there is a reversing device implanted in the patient for reversing the function performed by the restriction device. Such a reversing function preferably involves enlarging and restricting the stoma opening by the restriction device, suitably in a stepless manner. In this connection, the control device suitably controls the reversing device, which may include a switch, to reverse the function performed by the restriction device. The reversing device may comprise hydraulic means including a valve for shifting the flow direction of a fluid in the hydraulic means. Alternatively, the reversing device may comprise a mechanical reversing device, such as a switch or a gear box.
Where the reversing device comprises a switch the control device suitably controls the operation of the switch by shifting polarity of energy supplied to the switch. The switch may comprise an electric switch and the source of energy may supply electric energy for the operation of the switch.
In accordance with a advantageous embodiment of the invention, the apparatus further comprises an energy storage device implanted in the patient for storing the energy of the second form and for supplying energy in connection with the operation of the restriction device. The implanted energy storage device preferably comprises an electric source of energy, such as an accumulator, a rechargeable battery or a combination of an accumulator and rechargeable battery.
The apparatus may further comprise a switch implanted in the patient for switching the operation of the restriction device and a source of energy implanted in the patient. This embodiment is particularly suited for applications where the energy transmission efficiency of the apparatus is insufficient, i.e. where the implanted restriction device is to perform more advanced operations. Such a source of energy preferably is a battery. Alternatively, the source of energy is an accumulator which also may store the energy of the second form.
In accordance with a first alternative, the switch is operated by the energy of the second form supplied by the energy storage device to switch from an off mode, in which the source of energy is not in use, to an on mode, in which the source of energy supplies energy for the operation of the restriction device. In this case, the implanted source of energy may comprise a battery, preferably having a life-time of at least 10 years, or an accumulator. However, other kinds of sources are also conceivable, such as a nuclear source of energy or a chemical source of energy.
In accordance with a second alternative, the apparatus further comprises a remote control for controlling the supply of energy of the implanted source of energy, wherein the switch is operated by the energy of the second form supplied by the energy storage device to switch from an off mode, in which the remote control is prevented from controlling the source of energy and the source of energy is not in use, to a standby mode, in which the remote control is permitted to control the source of energy to supply energy for the operation of the restriction device.
In accordance with a third alternative, the energy storage device is omitted, wherein the switch is operated by the energy of the second form supplied by the energy transfer device to switch from an off mode, in which the remote control is prevented from controlling the source of energy and the source of energy is not in use, to a standby mode, in which the remote control is permitted to control the source of energy to supply energy for the operation of the restriction device.
In accordance with a fourth alternative, also the remote control is omitted, wherein the switch is operated by the energy of the second form supplied by the energy transfer device to switch from an off mode, in which the source of energy is not in use, to an on mode, in which the source of energy supplies energy for the operation of the restriction device. Where applicable, in the described embodiments the switch may switch when the energy transmission device is transmitting wireless energy, preferably while the transferred energy of the second form is stabilized by an implanted capacitor, which may temporarily (for a few seconds) store the energy of the second form.
The switch mentioned above may comprise an electronic switch or, where applicable, a mechanical switch.
The advantage of using a switch above all is increased control safety, i.e. interfering signals in the patient""s surroundings cannot affect the implanted restriction device. Furthermore, the lifetime of the implanted source of energy will be significantly prolonged, since the energy consumption of the apparatus will be reduced to a minimum. During the above mentioned standby mode, the remote control uses energy from the implanted source of energy. By means of the energy transmission device energy may be transmitted to activate the switch to connect the implanted source of energy only when energy is required in connection with the operation of the restriction device.
All of the above embodiments may be combined with at least one implanted sensor for sensing at least one physical parameter of the patient, wherein the control device may control the restriction device in response to signals by the sensor. For example, the sensor may comprise a pressure sensor for directly or indirectly sensing the pressure against the restriction device, human tissue or in the stomach or esophagus. The pressure sensor may be any suitable known or conventional pressure sensor such as shown in U.S. Pat. Nos. 5,540,731, 4,846,181, 4,738,267, 4,571,749, 4,407,296 or 3,939,823; or an NPC-102 Medical Angioplasty Sensor. The control device may comprise an internal control unit implanted in the patient for, preferably directly, controlling the restriction device in response to signals from the sensor. In response to signals from the sensor, for example pressure, the patient""s position or any other important physical parameter, the internal control unit may send information thereon to outside the patient""s body. The control unit may also automatically control the restriction device in response to signals from the sensor. For example, the control unit may control the restriction device to further restrict the food passageway in the stomach in response to the sensor sensing that the patient is lying, or enlarge the food passageway in response to the sensor sensing an abnormally high pressure against the restriction device.
Alternatively, the control device may comprise an external control unit outside the patient""s body for, suitably directly, controlling the restriction device in response to signals by the sensor. The external control unit may store information on the physical parameter sensed by the sensor and may be manually operated to control the restriction device based on the stored information. In addition, there may be at least one implanted sender for sending information on the physical parameter sensed by the sensor.
An external data communicator may be provided outside the patient""s body and an internal data communicator may be implanted in the patient for communicating with the external communicator. The implanted communicator may feed data related to the patient, or related to the implanted restriction device, back to the external communicator. Alternatively or in combination, the external communicator may feed data to the internal communicator. The implanted communicator may suitably feed data related to at least one physical signal of the patient. The arrangement of external and internal communicators gives the advantage, among other things, that a long term control of activities related to the implanted restriction device.
The apparatus may further comprise an implanted programmable control unit for controlling the restriction device, preferably over time in accordance with an activity schedule program. This will advance the apparatus and make possible an adaptation of the apparatus to the individual patients.
All of the above embodiments are preferably remote controlled. Thus, the apparatus advantageously comprises a wireless remote control transmitting at least one wireless control signal for controlling the restriction device. With such a remote control it will be possible for a doctor to readily adapt the function of the apparatus to the patient""s need, which is beneficial with respect to the treatment of the patient in the long run.
The wireless remote control may be capable of obtaining information on the condition of the implanted restriction device and of controlling the restriction device in response to the information. Also, The remote control may be capable of sending information related to the restriction device from inside the patient""s body to the outside thereof.
In a particular embodiment of the invention, the wireless remote control comprises at least one external signal transmitter or transceiver and at least one internal signal receiver or transceiver implanted in the patient. In another particular embodiment of the invention, the wireless remote control comprises at least one external signal receiver or transceiver and at least one internal signal transmitter or transceiver implanted in the patient.
The wireless remote control may transmit a carrier signal for carrying the control signal, wherein the carrier signal is frequency, amplitude or frequency and amplitude modulated and is digital, analog or digital and analog. Also the control signal used with the carrier signal may be frequency, amplitude or frequency and amplitude modulated.
The control signal may comprise a wave signal, for example, a sound wave signal, such as an ultrasound wave signal, an electromagnetic wave signal, such as an infrared light signal, a visible light signal, an ultra violet light signal, a laser signal, a micro wave signal, a radio wave signal, an x-ray radiation signal, or a gamma radiation signal. Where applicable, two or more of the above signals may be combined.
The control signal may be digital or analog, and may comprise an electric or magnetic field. Suitably, the wireless remote control may transmit an electromagnetic carrier wave signal for carrying the digital or analog control signal. For example, use of an analog carrier wave signal carrying a digital control signal would give safe communication. The control signal may be transmitted in pulses by the wireless remote control.
Alternatively, in the above embodiments a semiconductor circuitry, a transistor circuitry or a microchip may be substituted for the element of the apparatus having positive and negative regions.
The energy transfer device of the apparatus may be implanted, for example subcutaneously, in the abdomen, thorax or cephal region, or other locations in the patient""s body.
In accordance with another aspect of the invention, there is provided an implanting method, comprising the steps of providing a food intake restriction apparatus as described above, cutting an opening in a patient""s mucosa in an orifice of the patient""s body, and implanting the energy transfer device in the patient""s body through the opening. Alternatively, the cutting step may comprise cutting an opening in the patient""s skin and the implanting step may comprise implanting the energy transfer device in the patient""s body through the opening.
In accordance with yet another aspect of the invention, there is provided a laparoscopic surgical method of implanting a food intake restriction apparatus, comprising: a) Placing at least two laparoscopic trocars within the patient""s body. c) Using at least one dissecting tool inserted through the laparoscopic trocars, dissecting the region of the esophagus or stomach. d) Introducing the restriction device through the trocars. e) Placing a restriction device of the apparatus in the dissected area in engagement with the esophagus or stomach to create a restricted stoma. And f) implanting an energy transfer device of the apparatus for transferring wireless energy into energy of a form suited for operating the restriction device. The method may further comprise postoperatively adjusting the restricted stoma in a non-invasive procedure, e.g. at least once during the first year after the surgical procedure, and typically a plurality of times in the first year.
It is the primary object of the present invention to provide a simple yet effective method and apparatus for morbid obesity in humans or animals. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.